Google Tag (GTM / GA4)
The industry standard for analytics and tag management.
Google Tag Manager (GTM) is a free tag management system that lets you deploy and manage all your marketing and analytics tags from one interface — no code deploys needed. GA4 is Google's current analytics platform, typically deployed through GTM.
Why you need it
GTM gives you full control over all tags on your site without relying on developers for every change. GA4 provides essential audience insights, traffic data, and conversion measurement that informs every marketing decision.
How to install
Create a GTM account at tagmanager.google.com. Add the GTM snippet to your <head> (first snippet) and immediately after the opening <body> tag (noscript iframe). Then add your GA4 Configuration tag inside GTM, set your Measurement ID, and publish.
How to verify
In GTM, click Preview to enter debug mode, then visit your site. The Tag Assistant panel shows which tags fired and on which events. For GA4, use the DebugView in Google Analytics to see real-time events.
Common issues
The most common mistake is loading GA4 both directly (gtag.js script) AND inside GTM — this causes double-counting. Always load GA4 through GTM only. Also ensure dataLayer is initialised before the GTM snippet fires.
Installation code
<!-- Google Tag Manager (head snippet — paste in <head>) -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
})(window,document,'script','dataLayer','GTM-XXXXXXX');</script>
<!-- End Google Tag Manager -->
<!-- Google Tag Manager (noscript — paste after opening <body> tag) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-XXXXXXX"
height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
<!-- End Google Tag Manager (noscript) -->Replace YOUR_PIXEL_ID with your actual ID from the platform's ads manager.
Frequently asked questions
What is the difference between GTM and GA4?
GTM is a container that manages and deploys tags. GA4 is the analytics platform that collects data. GTM deploys GA4 — and also deploys Facebook Pixel, LinkedIn tags, and any other tracking code.
How do I check if Google Tag Manager is installed?
Enter your domain in PixelSpy above. You can also view your page source and search for "GTM-" to find the container ID. Google's Tag Assistant Chrome extension also confirms GTM presence.
Should I use GTM or install tags directly?
Always prefer GTM. Direct tag installation requires a developer for every update, creates version control issues, and risks duplicate firing when tags are later added to GTM anyway.